Steam-boiler



(No Model.)

G. G. TINDALL.

STEAM BOILER.

No. 325,027. P nte Aug. 25, 1885.

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ATTORNEYS.

NiTnn STATES PATENT OFFICE.

GEORGE G. TINDALL, OF OAKLAND, OALIFORNTA.

STEAM-BOILER.

SPECIFICATION orming part of Letters Patent No. 325,027, dated August 25, 1885.

Application filed February 27, 1885.

To (ZZZ whom it may concern.-

Be it known that I, GEORGE G. TINDALL, of Oakland, in the county of Alameda and State of California, have invented a new and Improved SteamBoiler, of which the following is a full, clear, and exact description.

The object of my invention is to improve the construction of steamboileraand more especially boilers of that class in which straw or like light substance is used for fuel, such as the boilers of steam -power thrashing ma- (-hines.

The invention consists in the construction and arrangement of parts, as will be hereinafter fully described and claimed.

Reference is to be had to the accompanying drawings, forming part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 is a central longitudinal sectional elevation of my improved steam-boiler. Fig. 2 is a vertical cross-sectional elevation of the boiler taken on the line as a", Fig. 1; and Fig. 3 is a rear end view of the boiler.

The letter A indicates the main shell of the boiler,which, above the fire-box B, has about a cylindrical crosssectional form, and is fitted with the ordinary lire-tubes, O, which extend clear through from the front head-plate, D, to the rear head-plate, E, of the boiler.

Back of the fire-box B the boiler-shell A is carried downward so it ineloses the larger lower fire-tubes, F, which open into the firebox, and, like the tubes O,extend clear through the rear end plate, E, of the boiler. The boiler-shell A thus has an oblong shape from the firebox B to its end plate, E. (See Figs. 1 and 3.)

I make the boiler-shell A preferably with the upper plate, a, which extends from end to end of the boiler, and downward at each side, and alower plate, a, which extends from the outer back plate, I), of the fire-box B to the rear end of the boiler and is riveted to the edges of the upper plate, a, and to the internal flange of the rear head, E, and to the outturned flange of the fire-box plate I). The front head or plate, 1), extends to the bottom ofthe water-leg or firebox of the boiler, as at D, Fig. 1.

As shown in Figs. 1 and 2, the fire-box B is built up of opposite inner side plates, 1) I),

(So model.)

with outer side plates, b If, spaced from plates 1) b to provide the usual water-circulation, and front and rear end plates, Z) I), the for ward ends of the lower-fire tubes, F, being set or expanded into the rear end plate, b. The lower ends of the plates D b b J b are fastened to the baseframe b of the fire-box.

The upper ends of the plates b I) are flanged, preferably, outward from the interior of the fire-box, to which flanges are riveted at a the front and rear edges of the downwardly-curving plate A, which also is riveted at a to the top edges of the opposite side plates, 1), and the opposite side parts of the plate A, curve outward and upward to the point or place of connection of the .main upper plate, a, with the opposite outer side plates, Z) b of the fire-box, where the plates (4 b" A are riveted together at a" a, as shown in Fig.

It will be seen that the plate A forms the lower part of the shell A above the firebox, and also the crown-sheet of the firebox, and as the plate A curves downward it is made self-bracing by its form, so that no stay-bolts are required for it, as are necessary with the flat or almost flat crown-sheet plates of fireboxes of the usual construction in boilers of this class, and by curving the crown-sheet A downward toward the center more room is given for the insertion of a larger number of long fire-tubes O for increasing the heatingsurface of the boiler. It will be seen that the crownsheet A may be riveted to the inner walls of the fire-box as a separate structure, which may afterward be riveted to the main body of the boiler, thus facilitating the construction of the boiler.

Stay-b0lts H are run horizontally across the boiler between the tubes 0 and about at the central part ofthe oblong portion of the boiler behind the firebox B to brace this part of the boiler-shell, which naturally is weaker than the cylindrical part of the shell above the firebox, and the lower row of braces H will range along the joints of the plates c a at the opposite sides of the boiler.

Front and rear smokebonnets of any approved kind will be fitted over the head-plates D E of the boiler, as indicated by the dotted lines I J, respectively, in Fig. 1, and so that products of combustion will pass from the firebox 13 rearward through the larger fire-tubes F, and then forward through the firetubes O to the Smokestack fitted to the smokebonnet I.

The fire-box B has a feed-opening, K, which may or may not have a door fitted to it, and th roughwhich opening the straw fuel is passed into the firebox.

The fire-grate consists of a series of tubes, L, closed at their inner ends and fitted at their outer open ends into the inner opposite side walls, I), of the fire-box, and preferably in pairs set in line across the fire-box, and so that the Water may enter the grate-tubes to prevent burning out of the tubes. The closed ends of the tubes lie quite closely to each other. (See Fig. 2.)

To provide for cleaning the interior of the grate-tubes without removing them, I fit suitable plugs, preferably screw-plugs M, in the outer walls or plates Z) of the fire'boxopposite each of the tubes L, and so that the plugs may be removed at any time to reach the interior of tubes L from the outside of the boiler.

I arrange the gratetubes L in a horizontal series, L, and a vertical series, L and so that the tubes at L will support the straw fuel above the bottom ofthe fire-box, and the tubes L by their disposal in front of the open ends of fire-tubes F, will prevent the fuel from being drawn in bulk against'or into these tubes, whereby choking up of the tubes will be prevented, and an efficient draft may be maintained to insure the most perfect and economical combustion of the fuel.

Beneath the steam-discharge pipe N of the boiler, and a short distance from the top of the shell-plate (I, I fix a plate, 0, which extends or arches over from one side of the boiler to the other, and reaches a considerable distance lengthwise of the boiler each way from the outlet N. The object of the plate 0 is to prevent the water in the boiler from passing out of the pipe N with the steam, or, in other words, to prevent priming.

I do not claim the hollow grate-bars nor the plate 0 in this application, reserving the right to file separate applications therefor.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. In a steam-boiler, the combination, with the vertical spaced walls of the fire-box, of the downward-curved crown-sheet secured at or near its edges to the upper edges of said walls, the fire-tubes G F, and the outer upper U shaped section, a, riveted at a to the outer wall and to the crown-sheet, said crown sheet forming the bottom of the forward end of the boiler, substantially as set forth.

2. A firebox steam-boiler shell constructed with upper plate or plates, a, lapping down its sides, lower plate or plates, a, riveted to the rear outer plate, I), of the firebox, and to plates a and rear head, E, a front head, D, extended at the front of the fire-box B, which consists of inner plates, 1) b 1) b and a con cavo-convex plate, A, riveted to the firebox plates and to the plates a, and constituting the crown-sheet of the firebox, substantially as herein set forth.

GEORGE G. TlNDALL.

Witnesses:

H. O. ALEXANDER, O. ALEXANDER. 

